Soil Physical Properties, Organic Carbon, and Total Nitrogen Affected by Tillage and Crop Rotation in Oklahoma.

Soil physical properties, organic carbon, and total nitrogen as affected by tillage and crop rotation in Oklahoma

Silvano L  Abreu, Chad B Godsey, Jeffrey T Edwards

Soil physical properties are severely affected by agriculture. Due to physical disturbance and severe alteration of its natural characteristics, soils under agricultural management are susceptible to change and also degradation. Among the most affected soil physical properties are soil compaction and alteration of aggregate characteristics. The objectives of this study was to evaluate OC, TN, soil penetration resistance and soil aggregate stability of soils under no-till (NT), conventional till (CT) and different crop rotations at two locations in Oklahoma. Several crop rotations under NT and CT were evaluated near Altus and Lahoma, OK after 5 year of management. Soil penetration resistance using a hydraulic driven probe was measured from 0 - 35 cm depth, soil wet aggregate stability at the depth of 0 to 10 cm, organic carbon (OC) and total nitrogen (TN) at the depths of  0 to 10, 10 to 20, 20 to 40, 40 to 70, and 70 to 110 cm were analyzed. No-till soils at Altus had greater OC (p<0.01) and TN (p<0.01) in the soil surface (0 to 10 cm) compared to CT. Differences at lower depths were not observed. At Lahoma, no difference in OC and TN content was observed between rotations at any depth. Penetration resistance was lower in soils under rotation compared to continuous cropping systems at Altus. Aggregate stability was also affected by tillage system at Altus, NT had larger aggregates in most treatments. Overall, the use of NT and crop rotation has increased soil quality parameters at Altus and Lahoma. However, the short period under NT management has not been enough to cause an effect in all evaluated properties and depth.